The synthesis of the first naturally occurring nitrogen mustard anti-tumor agent 593A (III, n equals 1, x equals C1) will be undertaken. The key step in the preparation will be a stereospecific intramolecular 1,3-dipolar addition of an omega-azido-alpha, beta-unsaturated ester (II). Stereochemistry will thus be controlled at the (two sets of) three chiral centers in the final product. The route chosen allows modification for the preparation of structural analogues. Specifically from a common precursor (I), bis-alkylating agents possessing different reactive groups, X, in the 3 position of 5,6, and 7 membered nitrogen heterocyclic rings (III), as well as bis-alkylating agents possessing a CH2X in the 2 position of nitrogen heterocycles of 5, 6, and 7 atoms (IV). These derivatives should possess potent antineoplastic activity, and will be submitted for testing of their anti-cancer activity.